Transformy

Object-oriented linear and nonlinear coordinate system transforms.

** This project is in early development; the list below is at least 50% wishful planning **

• A collection of different types of coordinate system transform classes with full unit test coverage
• Easy methods for mapping coordinate data through these transforms
• Transform composition and simplification
• Automatic generation of composite transforms from a coordinate system graph
• Coordinate arrays that know which coordinate system they live in to handle automatic mapping
• Conversion of transforms between ITK, Qt, scikit-image, vispy, etc.

Examples

Scale and translate 2D coordinates:

import numpy as np
from transformy import *

coords = np.array([
    [ 0,  0],
    [ 1,  2],
    [20, 21],
])

tr = STTransform(scale=(10, 1), offset=(5, 5))

tr.map(coords)
# returns:
# [ [  5.,  5.],
#   [ 15.,  7.],
#   [205., 26.]  ]

Compose multiple transforms together:

tr1 = STTransform(scale=(1, 10, 100))

tr2 = AffineTransform(dims=3)
tr2.rotate(90, axis=(0, 0, 1))

tr3 = CompositeTransform([tr2, tr1])

tr3.map(coords)

Todo

• import bilinear, SRT transforms from pyqtgraph
• import coordinate system graph handling from vispy
• make coordinate system dimensionality explicit
• unit tests against ITK output

Credit

Transformy is adapted from code originally written for VisPy (vispy.org), inspired by the nice transform classes in ITK, and maintained by the Allen Institute for Brain Science.